METHOD FOR GESTURE DETECTION, OPTICAL SENSOR CIRCUIT, IN PARTICULAR AN OPTICAL SENSOR CIRCUIT FOR GESTURE DETECTION, AND OPTICAL SENSOR ARRANGEMENT FOR GESTURE DETECTION

• US 20160070358A1
• Filed: 04/04/2014
• Published: 03/10/2016
• Est. Priority Date: 04/09/2013
• Status: Active Grant

• Current Assignee: ams AG (Ams-Osram AG)
• Original Assignee: ams AG (Ams-Osram AG)
• Inventors: TRATTLER, Peter, MANNINGER, Mario
• Granted Patent: US 9,791,935 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/017 Gesture based interaction, e.g. based on a set of recognized hand gestures interaction based on gestures traced on a digitiser G06F3/04883
• CPC Class Codes: G06F 3/0304 Detection arrangements using opto-electronic means constructional details of pointing devices not related to the detection arrangement using opto-electronic means G06F3/033; optical digitisers G06F3/042
• CPC Class Codes: G06V 40/28 Recognition of hand or arm movements, e.g. recognition of deaf sign language static hand signs G06V40/113

Abstract

A method for gesture detection comprises pre-processing and main-processing steps, wherein the pre-processing comprises emitting light using a light emitting device and generating of directional sensor signals as a function of time by detecting a fraction of the emitted light reflected by means of a movable object using a directional light sensor array). The main-processing comprises calculating coordinates as a function of time by using the directional sensor signals, being indicative of a position of the object with reference to a plane parallel to a principal plane of the light sensor array, and detecting a movement of the object depending on the timing of the coordinates.

Claims

1. A method for gesture detection comprising pre-processing and main-processing steps, wherein the pre-processing comprises:

emitting light in a pulsed manner with pulse-on phases followed by pulse-off phases using a light emitting device,

generating ambient signals depending on ambient light incident on a directional light sensor array during pulse-off phases of the emitted light,

generating light signals as a function of time by detecting a fraction of the emitted light reflected by means of a movable object during pulse-on phases of the emitted light using the directional light sensor array, and

calculating directional sensor signals as a function of time by adjusting the light signals with the ambient signals, and

wherein the main-processing comprises;

calculating coordinates as a function of time by using the directional sensor signals, being indicative of a position of the object with reference to a plane parallel to a principal plane of the light sensor array, and

detecting a movement of the object depending on the timing of the coordinates.

2. The method for gesture detection of claim 1, wherein the main processing further comprises:

generating filtered coordinates from the coordinates by means of at least one filter having a time constant, and

detecting the movement of the object depending on the timing of the filtered coordinates.

3. The method for gesture detection of claim 2, wherein the generation of filtered coordinates from the coordinates involves several filters, each filter having a different time constant.

4. The method for gesture detection of claim 2, wherein the generation of the filtered coordinates involves band pass filtering.

5. The method for gesture detection of claim 2, wherein the detection of the movement further depends on comparing, within a predetermined time-frame, the coordinates and/or filtered coordinates with detection thresholds, respectively.

6. The method for gesture detection of claim 1, wherein the main processing further comprises estimating a further coordinate by using an amplitude of the directional sensor signals, being indicative of a position of the object at a given time and with reference to an axis being orthogonal to a principal plane of the light sensor array.

7. The method for gesture detection of claim 1, wherein the pre-processing further comprises the step of adding or subtracting an offset value, in particular a constant offset value, to each of the directional sensor signals.

8. The method for gesture detection of claim 1, wherein the pre-processing further comprises the steps of:

determining for each of the directional sensor signals if it complies with respective threshold values,

providing those of the directional sensor signals (CH1, CH2, CH3, CH4) that comply with their respective threshold values (Tx, Ty, Tsum).

9. The method of claim 1, wherein the coordinates are limited to an interval by applying a limiting function to the directional sensor signals, in particular to a ratio of the directional sensor signals.

10. The method for gesture detection of claim 1, wherein the pre-processing and/or main-processing further comprises the steps of:

applying a scaling factor to the directional sensor signals and/or

applying a distance function to the directional sensor signals.

11. The method for gesture detection of claim 1, wherein the coordinates are calculated as a first coordinate x_coord and as a second coordinate y_coord according to the formulae

x_coord=(CH1−

CH2)/(CH1+CH2) and

y_coord=(CH3−

CH4)/(CH3+CH4)

and/or according to the formulae

x_coord=tan h(CH1/CH2) and

y_coord=tan h(CH3/CH4)

and/or according to the formulae

x_coord=exp(CH1/CH2) and

y_coord=exp(CH3/CH4).

12. (canceled)

13. (canceled)

14. An optical sensor circuit, in particular an optical sensor circuit for gesture detection, comprising:

an input terminal for a light emitting device to be connected, the light emitting device being configured to emit light in a pulsed manner with pulse-on phases followed by pulse-off phases,

a control unit connected to the input terminal,

an analog-to-digital converter connected to the control unit,

a directional light sensor array coupled to the control unit, and designed

to generate ambient signals depending on ambient light incident on the light sensor array during pulse-off phases of the emitted light, and

to generate light signals indicative of a fraction of the emitted light reflected by means of a movable object during pulse-on phases of the emitted light, and

a signal processing unit comprising an output terminal, the signal processing unit connected to the analog-to-digital converter and designed for recording the ambient signals and the light signals and for calculating and recording directional sensor signals as a function of time (t) by adjusting the light signals with the ambient signals.

15. The optical sensor circuit of claim 14, wherein the analog-to-digital converter (ADC) comprises

a linear analog-to-digital converter,

a logarithmic analog-to-digital converter or

a linear analog-to-digital converter further comprising a stage for converting from linear to logarithmic domain.

16. The optical sensor circuit of claim 14, wherein the light sensor array comprises directional photo-diodes each photo-diode being arranged within the light sensor array such as to detect light in a predominant direction.

17. The optical sensor circuit of claim 16, wherein each directional photo-diode is placed in front of an end of a channel within the light sensor array, each channel having a principal axis defining a respective predominant direction.

18. The optical sensor circuit, of claim 14, wherein the signal processing unit comprises

a signal recording unit to record directional sensor signals as a function of time and

an offset compensation unit to adjust an offset in the directional sensor signals.

19. The optical sensor arrangement for gesture detection comprising an optical sensor circuit of claim 14, and further comprising a calculation unit connected to the output terminal, wherein the calculation unit comprises

a coordinate unit to calculate coordinates as a function of time and indicative of a position of the object in a plane parallel to a principal plane of the optical sensor circuit depending on the directional sensor signals, and

a filter unit to detect a movement of the object depending on the timing of filtered coordinates.

20. The optical sensor arrangement of claim 19, wherein the filter unit comprises one or more band pass filters and is configured to reject movements with a velocity within one or more velocity ranges.

21. The optical sensor arrangement of claim 19, the calculation unit comprises a comparison unit to compare, within a predetermined timeframe, the coordinates and/or the filtered coordinates with detection thresholds, respectively.

22. The optical sensor arrangement of claim 19, wherein the calculation unit and/or signal processing unit comprises a function unit to scale the directional sensor signals and to apply a distance function to the scaled directional sensor signals.

23. The optical sensor circuit of claim 14, wherein each channel is defined by openings in a layer of several metal sheets placed on top of each other with certain spacing and the openings are shifted with respect to each other so as to define the respective principal axis defining the respective predominant direction.

24. A method for gesture detection comprising pre-processing and main-processing steps, wherein the pre-processing comprises:

emitting light using a light emitting device, and

generating of directional sensor signals as a function of time by detecting a fraction of the emitted light reflected by means of a movable object using a directional light sensor array, and

wherein the main-processing comprises;

calculating coordinates as a function of time by using the directional sensor signals, being indicative of a position of the object with reference to a plane parallel to a principal plane of the light sensor array, and

detecting a movement of the object depending on the timing of the coordinates.